TABLE 1

Stability of XP13512 in buffer and tissues in vitro All incubations were for 1 h at 37°C. The initial XP13512 concentration was 5 μM. Gabapentin lactam was not detected in any of the incubations (<1% release).

Tissue Preparation
XP13512 Remaining
Gabapentin Released
%
Buffer, pH 2.0 98 NDa
Buffer, pH 7.4 99 ND
Buffer, pH 8.0 95 ND
Pancreatinb 52 43
Caco-2 S9c 18 75
Rat plasma, 90% 47 45
Human plasma, 90% 96 5
Rat liver S9d 25 71
Human liver S9d
4
81

  • ↵ a ND, not detected (<1%)

  • ↵ b Porcine pancreatin was 10 mg/ml in pH 7.5 buffer

  • ↵ c Caco-2 was 0.5 mg protein/ml at pH 7.4

  • ↵ d Liver S9 contained 0.5 mg/ml protein and 1 mM NADPH at pH 7.4